Dye lasers, and particularly organic dye lasers, have certain, unique features. Depending on the specific dye in the laser, the output wavelength is tunable over a bandwidth of approximately 100 nanometers. Dye lasers can operate from the ultraviolet to the infrared, and a single laser resonator cavity can be used to cover this entire wavelength range simply by changing dyes and coatings on the intra-cavity optical components.
Recently, there have been attempts to make dye laser gain elements that incorporate a dye impregnated in a plastic host such as modified polymethyl methacrylate (MPMMA) to provide a solid state laser gain element. MPMMA has excellent optical characteristics (clarity, low number of bubbles and inclusions, surface quality), and when used as a dye host, does not greatly affect the gain and spectral characteristics of the dye. Unfortunately, MPMMA has poor thermal conductivity so that gain elements made of this material can exhibit thermal lensing, thermal distortion, and even melting. Typically, such gain elements are made at room temperature by mixing a certain concentration of the dye with the modified MMA monomer in solution. The mixture is then polymerized to form the solid MPMMA, and the rough form is cut and polished to produce the final shape of the gain element. Because the dye is quite sensitive to high temperature, the manufacturing must take place at temperatures that do not significantly exceed room temperature. Embedding the dye in high melting temperature materials such as glass is therefore not possible. In part, due to these thermal problems, other solid state materials such as porous glass and sol-gels have been used as host structures because they are have a higher thermal conductivity than MPMMA. However, gain elements made of porous glass or sol-gels are more difficult to fabricate and may not provide as much gain compared to plastic hosts. A need therefore exists for a dye laser that uses a solid state host, but which is not subject to the aforesaid thermal problems.
A laser includes a first optically reflective element; a second optically reflective element aligned with and opposed to the first optically reflective element to define a laser cavity having an optical axis; an optical pump source for injecting optical pump energy into the laser cavity along the optical axis; a thin solid-state dye gain element having a plastic host in which a dye is dissolved that is interposed between said first and second optically reflective elements along the optical axis for transforming said optical pump energy into a resonant optical signal; and a cooling element in thermal contact with the solid-state dye gain element for absorbing heat energy from the solid-state dye gain element to control the temperature of the solid-state dye gain element.